JPS6216717A - Rice cooker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Technical Field of the Invention 1] The present invention relates to a rice cooker that obtains a boiling detection signal when water in a pot reaches a boiling state and uses this boiling detection signal to control rice cooking. [Technical background of the invention and its problems 1 Recent rice cookers have various rice cooking controls, specifically, for example, the time until the water in the pot boils when cooking white rice. By generating heat using human power for cooking rice, the well-known condition f1 for deliciously cooking rice is satisfied, and the boiling temperature is also satisfied. Afterwards (11-M), reduce the heater output to prevent the rice from burning, and (11-M) cook the rice deliciously and control the clay pot, or when cooking porridge, the water in the pot will boil and the IC Afterwards, the output of the rice-cooking heater is reduced.
When performing such 2R control, it is necessary to detect whether or not the water in the pot has reached a boiling state. However, with conventional rice cookers, it is generally best to detect the temperature of the steel and determine that it is in a boiling state when the detected temperature reaches a predetermined upper limit temperature of 10 hours. Re-
(In this case, to accurately detect the boiling state by 1F,
It is desirable to set the metering semi-exhaustion near 100'C. However, in this way the upper limit temperature can be set to 1C) 0℃
If they are set close to each other, the contact condition between the temperature sensor and the steel for detecting the pot temperature, variations in the circuit constants of the temperature sensor and changes in its characteristics over time, changes in atmospheric pressure, or Due to fluctuations in the boiling point due to seasonings being added to the pot when making rice, the boiling state cannot be detected no matter how long the pot is boiling. In reality, in anticipation of such fluctuations, the upper limit temperature is set at around ε30°C. For this reason, conventional rice cookers have the problem of extremely inaccurate detection of the boiling state in the pot, which in turn makes it impossible to accurately control rice cooking. [Object of the Invention] The present invention was made in view of the circumstances described in 1-C, and its object is to be able to extremely accurately detect the boiling state of water in a pot regardless of whether the steel is used for cooking rice; Based on the detection results, it is possible to reduce the heater output at the exact time after the water in the pot has boiled, thereby controlling the rice to be cooked deliciously or preventing porridge from boiling over when cooking. To provide a rice cooker which can accurately perform the above operations, and can also automatically compensate when a boiling state is erroneously detected due to external factors. [Summary of the Invention] In order to achieve the object described in item 1-1, this invention is based on a method that determines that a boiling state occurs when the time-series temperature gradient of the pot temperature becomes less than or equal to a predetermined target temperature gradient. A boiling detection means for outputting a boiling detection signal is provided, as well as a heater output control circuit for reducing the output of the heater for cooking rice when the boiling detection signal is outputted, and a heater output control circuit for reducing the output of the rice cooking heater when the boiling detection signal is outputted. boiling detection compensating means configured to memorize the steel wet turtle and subtract a certain compensating temperature value from the memorized value, and then increasing the output of the heater when the pot temperature decreases to the subtraction result; In addition, a rice cooking amount detection means that outputs a rice cooking amount signal according to the amount of rice cooked is installed respectively.

[), the boiling detection means is configured to change the target temperature gradient so that the larger the amount of cooked rice indicated by the l-distributed rice hanging signal is, the smaller the target temperature gradient becomes. [Embodiments of the Invention] A first embodiment of the present invention will be described below with reference to FIGS. 1 to 6. In Fig. 2, 1 is the rice cooker body consisting of the inner frame 2 and outer frame 3, etc., 4 is the lid, 45 is the steel removably housed in the inner frame 2, and 6 is the heating chain 5. For example, a rated output of 60 is installed in the space between the bottoms of the inner frame 2 and outer frame 3.
This is a 0 watt rice cooking heater. 7 is the bottom of the inner frame 2 C4
It is arranged so that it can be moved downwardly so that it can pass through.
X heat sensitive-1 guy 1, this (J 111 smell-CfF
When the steel is housed in the inner frame 2, the steel is pushed to the outside bottom of the inner frame 2. For example, as a heat-sensitive element, a reamister, 1
0 is a steel switch for dry cooking prevention IV that is pressed 1F by the heat-sensitive switch 7 only when the steel 5 containing rice and water is stored in the inner frame 2 and in the 1= state. , 11
is the operation panel installed on the side of Cooking Rice Book 141, 12
is a case arranged on the outer bottom of the rice cooker main body 1, and inside this case 12 there is an irH record 1] that turns on and off the heater 6 based on the temperature detected by the mister 9 and the input from the operation panel 11. A control circuit 13 for controlling electricity is housed therein. FIG. 1 shows the configuration of the control circuit 13 and its related parts that are directly related to the gist of the present invention, and will be described below. In FIG. 1, the control circuit 13 is shown in a bar code form by combining each functional part, but the present invention is not limited to this. Of course, they may be replaced. In FIG. 1, reference numeral 14 denotes a switching element, for example a triac, which is connected between both terminals of an AC voltage ITIk 15 via the heater 6 and the steel switch 10 in series. , 16 is a small hekabra consisting of a photodiode 16a and a transistor 16b, and the light emitting diode 16a is provided with a half-wave voltage of the AC power supply 15 through a diode 17 and a resistor 18. ing. Reference numeral 19 denotes a DC constant voltage circuit that receives the output of the AC power 115, and power is supplied from the output lines la and lb of A to each (B) path section described below. 20 is a differential circuit, for example. This is an initialization circuit that outputs an initialization pulse F]o every time the power is turned on. 21 is a rectangular shape that outputs the outputs of the above-mentioned E1 to coupler 16 (voltage output corresponding to the half-wave output of the AC N source 15). A waveform shaping circuit that shapes waves into waves,
22 divides the output of the waveform shaping circuit 21 and generates an intermittent signal, for example, a one-second period pulse ()1.
The first frequency dividing circuit 23 divides the -1- clock pulse P1 and fails at a time of 16, for example, 10.
This is a second frequency dividing circuit which outputs a clock pulse P2 having a period of 0 seconds. 24 with the 4J-Mr. 9? fiA
△=1] converter that constitutes the degree detection means 25, which is 1
The f-mister 9 outputs a digital humidity detection signal Sd corresponding to the temperature of the steel 5 detected. 26 and 27 are first and second temperature value storage units that store values corresponding to temperatures used to detect the amount of cooked rice, such as 70°C and 80°C, respectively; 28 is a predetermined lower limit temperature, such as 90°C; The third temperature value storage section 29 that stores corresponding numerical values is, for example, 1
This is a fourth temperature value storage unit that stores a numerical value corresponding to 10°C. Further, 30 to 39 are fifth to fourteenth temperature value storage sections, in which, for example, the following numerical values are stored, as shown in FIG. That is, the fifth temperature value storage unit 30 stores a value corresponding to 2°C, and the sixth temperature value storage unit 31 stores a value corresponding to 3°C, which is the compensation temperature value.
Numerical value corresponding to C, 8th and 11th temperature value storage unit 33
and 36 respectively store numerical values corresponding to 3°C, and the seventh
The tenth temperature value storage units 32 and 35 each store a numerical value corresponding to 1°C, and the ninth and twelfth temperature value storage units 34 and 37 store a numerical value corresponding to 5°C, respectively. The heater power-off temperature D is stored in the thirteenth temperature value storage section 38.
The value corresponding to 112 degrees Celsius is memorized in the 14th
The temperature value storage unit 39 stores a value corresponding to 103° C. as the heating start temperature pr for 7° cooking. Reference numerals 40 and 41 designate first and second time value storage units that store numerical values corresponding to, for example, 2 minutes and 4 minutes, respectively, as a reference value when detecting the cooking fQI amount. Reference numerals 421 to 51 are third to twelfth time value storage sections, in which, as shown in FIG. 1, for example, the following numerical values are stored. That is, the third time value storage section 42 stores a numerical value corresponding to 7 minutes, the fourth time value storage section 43 stores a numerical value corresponding to 9 minutes, and the fifth and eighth time values are stored. The number storage units 44 and 47 respectively store numerical values corresponding to 0 seconds, the sixth and ninth time value storage units 45 and 48 respectively store numerical values corresponding to 10 seconds, and the seventh and ninth time value storage units 45 and 48 store numerical values corresponding to 10 seconds, respectively. The tenth time value storage units 716 and 49 each store a value corresponding to 20 seconds, and the eleventh time value storage unit 50 stores a value corresponding to 30 seconds as the double cooking heating reference time N. and the first
1 as the uneven driving time M is stored in the time value storage unit 51 of 2.
Numerical values corresponding to 5 minutes are memorized. 52 to 64 are comparison circuits, and these are input terminals A and 13.
When each input value for A≧13, the output terminal C
A high level signal is output from output terminal C, and a []-level signal is output from output terminal C at the end of the relationship A<[3. Ma lζ,
Reference numeral 65 denotes a comparator circuit equipped with an enable terminal [-n, which performs the same operation as the comparator circuits 527'l to 64 described above only when the enable terminal [n receives a high level signal (J). When terminal Fn receives an L-level signal, a low-level signal is always output from output terminal C. 66 and 67 t; U subtraction circuits that subtract the human power value for the input terminal [ from the human power value for the input terminal [], and output the subtraction result from the output terminal [-]. 68 to 71 are addition i1 circuits, which input the input value for the input terminal x and the input 1lri for the input terminal Y.
is added to IS, and the added value is output from the output terminal /. 72 to 75 beams [-1 to 1 to 1 and the number of input pulses for the pane CK are outputted from the output terminal Q to the counter C1 and its reset terminal R.
l) Runt contents are initialized when a pulse signal is received. 76 to 79 are trigger circuits,
When the input signal rises by tt, a trigger pulse P3 is output for a short time. 80f is a delay circuit, which delays the input signal by a short period of time before outputting it. 81
For example, is a shift register that has 24 middle-level registers, and every time a pulse signal is received at the cross terminal φ, the human power applied to the data terminal is transferred to the first [-1 middle-level register. When a pulse signal is received at the reset terminal R, the old stored data is sequentially shifted to the upper unit register each time new data is read. It is necessary to initialize the stored data. Then, in such a shift register 81, the 12th unit register 81
b, the 18th medium-level register 81G, and the 24th single-level register 81d. 82 is a memory circuit, which is L
The input terminal R is configured to be initialized upon receiving a pulse signal at the input terminal R, and from this initialized state, the value input for the first time to the input terminal is stored. . 83 is a heater drive circuit which outputs a gate signal P S and supplies it to the gate terminal of the triac L4 only when receiving a high level signal; 84 is a heater output control circuit which is driven only when receiving a high level signal; When the heater output control circuit 84 is driven, it outputs a pulsed control signal SC with a decoupage ratio of 50%, for example. Reference numerals 85 to 100 are 1 to RANSFAGE-1-, which exhibit a conductive state only when a high level signal is received at the GU1 to terminals. Reference numerals 101 and 102 are a start switch for starting rice cooking and a stop switch for stopping rice cooking, which are provided on the operation panel 11, respectively, and these are constituted by momentary type push button switches, and respond only when A is operated. Pulse signals (high level signals) P4 and P5 are output to the lines, respectively. Also, 103 to 105 are R-S
Flip-flops, 106 to 115 are ANI''J circuits, 116 to 118 are OR circuits, and 119 to 125 are inverters.
and the AND circuit 108 constitutes -C81 time means 126, and the first . The second temperature value storage unit 26°27, the first .
Second time candy storage unit 40, 41. Comparison circuits 52, 53,
56, 57. Counter 72°ANr) circuit 106, 10
9 and inverters 119 and 120 constitute a cooking amount detection means 127, and a fifth temperature value storage section 30. Comparison circuit 65. The boiling detection means 128 is constituted by the subtraction circuit 66, the shift register 81, and the transfer gates 1 to 85, 86, and 87, and includes two fourth temperature value storage sections, a third time value storage section, a fourth time value storage section <2. <3. Comparison circuit 58°59. Counter 73. A correction means 129 is constituted by the circuits 107, 110 and the inverters 121, 122, and includes the fourteenth one-time value storage section 39, the fifth to twelfth time period storage sections 44 to 51. Comparison circuits 62, 63, 64.
Kashin circuit 70.71° counter 74, 75. 1-Route 78.79.1-Lancefj.Goo 1-95
〜100. A double cooking control means 130 is constituted by the AN[1 circuit 11/1.115 and the inverter 125, and further includes a sixth temperature value storage section 31. Comparison circuit 60. Stem reduction circuit 67゜memory circuit 82 and transformer foot goo 1 to 8
The boiling detection compensating means 131 is constituted by -C. Next, the operation of the above structure will be explained with reference also to FIGS. 3 and 4. Incidentally, Fig. 3 (A> and (B)) respectively show the time change characteristics of the detected temperature (i.e., the temperature of the steel 5) of the thermistor 9 +ZJ and the output of the -thermistor 6, and Fig. 4 shows is the comparison circuit 52゜53.5'l, 55.60
,61,62,63,64.65. Heater output control circuit 84. Star 1~Swip 101. R-S flip-flop 103. Each set output of 10'l, 105 *η; Child Q, AND circuit 106, 107, 113, 115. Each of the 14 output waveforms from the OR circuit 118 is shown in FIG. That is, when 8A5 containing rice and the required amount of water is stored in the inner frame 2, the steel switch 10 hKΔ
will be turned on. When the power is turned on in this state, the DC power supply circuit 19 and the coupler 16 are driven, and the initialization circuit 20 outputs the initialization pulse Po.
This one initialization pulse causes the "cR-S flippuff"
The l knob 103 is reset and a high level signal is output from its reset/output terminal d, and this high level signal initializes the output terminals 2, 74 and the memory circuit 82, and the R -S flip 1] Tube 105
is reheated. Also, at this time, the above R-S
Since the trigger pulse 1]3 is output from the trigger circuit 76 to 1 which receives the high level signal from the flip 70 knob 103 via the OR circuit 117, the trigger pulse 1]3
Shift 1 to register 81 are initialized by
The high level signal outputted through the same <OR circuit 117 resets the [(-S flip-flop 104. After that, time 1''. (See FIGS. 3 and 4)
When the start switch 101 is turned on, the R-8 flip-flop 103 is set by the pulse signal P4 outputted in response to the on-state of A, and the high level signal from the set/output terminal Q is output to the A N D circuit 112.゜1
given to 13. At this time, one A11) circuit 11
2 is given the low level signal from the cell 1 to output terminal Q of the R-S flip-flop 104 which is in the reset 1 to 1 state as described above, so its output remains a low level signal. , the other ANI') circuit 113 is supplied with the [1-level signal from the cell 1 output terminal Q of the R-S flip-flop 104 after being inverted to a high level signal by the inverter 124, and is also supplied with a reset signal. 1 to state [ku-S flip-flop 10
Since the high-level signals from the output terminals 1 to 0 of No. 5 are applied, a high-level signal is output from the A N circuit 113 in a cohesive manner and is applied to the heater drive circuit 83. Therefore, the goo mill signal Sg is output from the heater drive circuit 83 to turn on the liac 14 to 1, and in response, the AC power supply 15 outputs the signal Sg to the steel switch 10.1-.
Electricity is supplied to the heater 6 via the liac 14 to heat the steel 5, and the rice cooking process is started in one step. As the rice cooking process progresses, the humidity of the steel 5 increases as shown in FIG. 33, and the temperature detection circuit 25 outputs a temperature detection signal Sd corresponding to the drying of the steel 5. Then, when the temperature of the steel 5 rises to 70° C. stored in the first temperature value storage section 26 (time t1), the rice cooking amount detection section 127 operates first. That is, the rice cooking amount detection section 127
, the comparator circuit 52 determines that the temperature detection signal Sd input to the terminal A is equal to the temperature value corresponding to r70°C input from the first temperature value storage unit 26 to the terminal [3]. A low level signal is output until time t1,
After time 1-1, a high level signal is output. In addition, the comparator circuit 531hL, the temperature test 111 Sd manually applied to its terminal [3] is -(second temperature 1.u) with respect to the terminal △
l111 At storage section 27h is manually operated [-80℃
Thirst corresponding to 1αIll'15L Time t
A high level signal is output until 2, and from time I2 onwards, [
Outputs a 1-level Shinkyu. Therefore, time tl~t2
A high level signal is output from both comparison circuits 52 and 53 only during the period 1)) and is applied to the A N lj'jl path 106. :+J first frequency divider circuit 22
1 is the AND circuit 106.
Pass through Ch round 72 glue [knock terminal CK! I can get it. In this IJ knot binding, the counter 72 counts (I5, the temperature of the steel 5 increases from 70°C to 80°C, : time - r - a (from time t1 1
[Time up to 2)] Therefore, the intercostal space [a] measured as described above has the property of increasing or decreasing in proportion to the amount of rice cooked, and corresponds to this time Ta ()
Counter 72's non-uncount t-1+++! The amount of cooked rice is determined based on J. That is, the first,
Each number before (
2 minutes, equivalent to 4 minutes). At this time, the comparator circuit 56 outputs a low level signal (if the value of the counter 72 is equivalent to 1 to 2 minutes) when the rice is lifted and the amount of rice cooked is relatively small. However, this [1-level No. 16 is transformed into a high-level signal, which is the rice cooking ω signal, by the inverter 119, and the line]-1
given to. In addition, the ratio φ☆ open circuit 7 shows that the count ff+ of the counter 72 corresponds to 4 minutes 1il'JJ's J- throat (
In other words, when the amount of rice to be cooked is relatively large), a high level signal, which is a cooking resistance signal, is outputted to lines 1-3 hλ. Furthermore, when the count of the counter 72 (target) is greater than or equal to a value equivalent to 2 minutes and less than a value equivalent to C months and 1 minute (in other words, when the amount of rice cooked is medium), a high level signal is output from the comparator circuit 56. This is applied to one input terminal A of the AND circuit 109, and a low level signal is output from the comparison circuit 57))
This signal is then transferred to the inverter 120, transformed into a high-level signal, and sent to the other input terminal of the AND circuit 109, thus connecting the A N f) circuit 10.
A high level signal as a rice cooking amount signal is outputted from the input terminal 9 and input to the input terminal 12. In short, the rice cooking amount detection section 127
is the hot water temperature of steel 0/buff 0℃ It takes 1 day to rise to 30℃/, = 114 The amount of rice to be cooked is determined based on #υ, and the rice cooking damage signal ( High level signal) to win [, I; 1. ．． 2, selectively outputs to L-3. If the detected amount of cooked rice is relatively small, the gate terminal is connected to the line Lt.
．． 89.95 accelerates the conduction state, and if the detected rice cooking is medium, the terminal 1 connected to line 1-2
If the gates 86 and 90.96 of the Heranshu T 7 are in a conductive state and the detected amount of cooked rice is relatively large,
7,91.97 becomes conductive. At this time, the transfer gate is selectively turned on as described above.
1-89.90. 7th version corresponding to '91. 8th. The temperature value stored in the ninth temperature value storage unit 32, 33, 34 is the heater power-off temperature Dz (the thirteenth temperature value storage unit 3
These stored temperature values are selectively applied to the input terminal Y of the adder circuit 68 according to the magnitude of the detected rice cooking amount. The adder circuit 68 converts the input vorticity factor into the numerical value (
It is added to the heater power-off temperature Dz> and output. M:
, the 5th .95.96.97 corresponding to 95.96.97 to the transfer game 1 which is also selectively conducted as described above. 6th゜7th
The time values stored in the time value storage units 44, 45, and 46 correspond to the Nigame cooking heating reference time N (the eleventh time value storage unit 5).
0 (ie, 30 seconds), and each of these stored time values is selectively given to the input terminal Y of the adder circuit 70 depending on the magnitude of the detected rice cooking amount. In the crimping circuit 70, the time value input in this manner is added to the numerical value (double cooking heating reference time N) stored in the eleventh time value storage section 50 and output. After this, when the temperature of 145 rises roughly and exceeds the lower limit temperature 190°C stored in the third temperature value storage unit 28 (time t3), the input of the comparison circuit 54 = 22- terminal A, f3 Each person's power (1r1 is 47 in the relationship of A≧[3, so that the output of each comparator circuit 5/l is inverted to a high level signal9, as a result, 1. The ANr1 circuit 108 which receives a high level signal at the input terminal of the input terminal 1) is connected to the input terminal 108 of the other terminal 1), i.e., the 10 second cycle from the second frequency divider circuit 23 in the means 126 at 61 o'clock. The comparator circuit 65 receives the high novel signal from the comparator circuit 54 via the delay circuit 80 to the enable terminal Fn. becomes operational, and accordingly, the boiling detection function of the -C boiling detection means 128 is enabled.In other words, in order for the pulse signal P2 to pass through the AND circuit 108, the pulse Since the signal [] 2 can be transferred to the shift terminal φ of the register F31, the register 81 inputs the temperature detection signal Sd to the data terminal every 10 seconds. At the same time, each time the main temperature detection signal Sd is read, the old temperature detection signal Sd is sequentially shifted to the middle register of rank F.As a result, the old temperature detection signal Sd is sequentially shifted to the middle register of F rank. is the current temperature detection signal S (temperature detection signal Sd 120 seconds (2 minutes) before I),
The middle register 81c of No. 18 contains a temperature detection signal j 180 seconds (3 minutes) before the current temperature detection signal Sli.
, j S d are stored in the 24th unit register 8
1d is 240 seconds (4 seconds) from the current temperature detection signal Sd.
(minute) previous temperature detection signal Sd is now stored. At this time, the above intermediate registers 8111, 810 and 81d
Each memory data corresponds to 1 Heransph I game 1
85, 86 and 87 to the input terminal F of the n-reducing circuit 66. However, as mentioned above, when the amount of rice to be cooked is relatively small, the transfer gate 85 quickly changes the conduction state to one point. The data stored in the unit register 811) is given to the input terminal F of the subtraction circuit 66, and
Similarly, if the amount of rice cooked is medium or relatively large,
Each stored data in intermediate registers 81c and 81d is applied to an input terminal of subtraction circuit 66. 1-Reduction stop circuit 6
Since the furniture detection signal 3d is directly input to the other input terminal of C1, the C1 reduction/stop circuit 66
corresponds to the reference time in the embodiment of the present invention from the value indicated by Kinkan's temperature detection No. 18 Sd 1) 2 minutes ago,
The numerical value indicated by the temperature detection signal Sd 3 minutes ago or 4 minutes ago is subtracted by 4 r. Temperature 1 of steel 5
-4 value, which in turn becomes a value corresponding to the time-series temperature gradient of steel 5. However, the temperature of the steel 5, that is, the temperature detection signal 3
The 14 ratio of d has the property of becoming approximately zero when the water in the steel 5 reaches a boiling state, and therefore! ”Junior 14
If it is detected that the wetness soil value of the steel 5 within the temperature range has become equal to or less than a predetermined comparative temperature value, it can be determined whether or not the inside of the steel 5 has reached a boiling state. In this case, since the temperature ratio of steel 5 tends to be dull when the amount of rice cooked is large,
In order to accurately detect boiling, it is desirable to change the reference time according to the amount of rice cooked. The reference time (i.e., 1 of the temperature detection signal Sd - the sampling time) is automatically changed to 2 minutes, 3 minutes, or 4 minutes as described above. And comparison circuit 6
5, the output from the subtraction circuit 66 (temperature rise value of the L-J steel 5 within the three-step reference time determined according to the amount of rice cooked) and the above-mentioned value are stored in the fifth temperature value storage section 30. The comparative temperature value is compared with the stored numerical value (equivalent to 2℃), and if the temperature threshold value of vA5 is less than 2℃ and 4f within the above reference time. , the comparison circuit 65
A boiling detection signal Sz having a high level of 48 is output from 48 (time i4). Therefore, in the case of a3 at time 1-4 of the F record, the memory circuit 82
When the memory contents of C1 are in an initialized state, the output of the subtraction circuit 67 that subtracts the numerical value (corresponding to 3°C) stored in the sixth temperature value storage section 31 from the stored value is the value of the angle. , the comparator circuit 60 is in a state of outputting a low level signal. Therefore, the reset terminal of the comparison circuit 60 and the R-S flip 70 knob 103 is connected to the input terminal of the OR-1 path 117.
A low level signal is returned from the output terminal 0, and this []-level signal is inverted to a high level signal by the inverter 123 and sent to the -h input terminal of the ANI) circuit 111. Therefore, when the boiling detection signal SZ (high level signal) is outputted at time 14 as described above, a high level signal is outputted from the A N l) circuit 111 and the R-S knob 70 knob 104 is set.
be done. When this is reversed, the output of the A N +', ) circuit 113, which had been outputting a high level signal, is inverted to an 11- level signal. A high level signal is applied from each cell 1 to output terminal Q of the -1 block 103 and 104 and the output terminal d of the R-S control flop 105.
1, a high level signal is output from the AND circuit 112, and in response, the C heater output control circuit 84
A pulse-like control signal +-48C with a duty ratio of 50% is outputted from J and -48C to be sent to the heater drive circuit 83. This bundled triac 14 is now turned on at a duty ratio of 50%, and at this time the rated output of the heater 6 is 600 watts + - (', so the heater 6 is
It generates heat with an output of 0 W[, that is, half the rated power at F8. Furthermore, when the R-S flip-flop 104 is set at time 14, the tri-power circuit 7
7 is driven and the trigger pulse P3 is output from now on, so the counter 73 is driven by the trigger pulse P3.
is initialized, and 88 to transfer game 1 becomes conductive, and the temperature detection signal Sd at time 14 (corresponding to the temperature of steel 5 at the time of detection of the boiling state) becomes It comes to be stored in the storage circuit 82. Also, at this point, there is enough water left in the steel 5 and the water temperature exceeds 100°C (7), so the temperature detection signal Sd corresponding to the temperature of the steel 5 is The comparator circuit 55 that compares the fourth temperature storage unit 29 with the record 1 centigrade (corresponding to 110°C) outputs a high level signal, and therefore the high level signal and the reset output of the R-S flip-flop 105 are output. The AND circuit 107 that has received the high level signal from the terminal d is in a state where it allows the pulse signal MPt (1 second period) from the first frequency dividing circuit 22 to pass.Therefore, it is initialized as described above. The count value of the counter 73 does not increase due to the elapsed time from time 1-4.Then, as the rice cooking process further progresses and the inside of the steel 5 reaches the so-called dry-up state, the The temperature of the steel 5 suddenly rises by -1. In this case, when the temperature of the steel 5 reaches 110°C at time t5, each of the input terminals A and 11 of the comparator circuit 55 Since the human power has a relationship of A<B and its output is inverted to a []-level signal, the ANr) circuit 107 passes the pulse signal P1 to l1, and the operation of the counter 73 to run 1 stops. It will be uploaded. Therefore, conclusively, the count value of the counter 73 is the required time Tb from time t4 when the boiling detection signal 3z is output to time t5 when the temperature of the steel 5 reaches 110°C.
(corresponds to the duration of the boiling state). The time l) measured as above is also the time t1 mentioned above.
Like the time Ta from 12 to 12, it has the property of increasing or decreasing in proportion to the amount of rice cooked, and also has the property of being influenced by the ratio of rice to water during cooking.
The amount of cooked rice detected by the amount of cooked rice detection means 127 is supplemented as follows based on the value of the counter of the counter 73 corresponding to . That is, the count value of the counter 73 is the value of the comparison circuit 58, 59.
By 3rd. The numerical values (corresponding to 7 minutes and 9 minutes) stored in the fourth time value storage section/12.43 are compared. At this time, the comparator circuit 58 outputs a low level signal as soon as the count value of the counter 73 is smaller than the value equivalent to 7 minutes (in other words, when the amount of rice cooked is relatively small), and this low level signal is turned to a high level by the inverter 121. It is inverted to a level signal and applied to line L4. Further, the comparison circuit 59 outputs a high level signal when the count value of the counter 73 is equal to or greater than the value equivalent to 9 minutes (in other words, when the amount of rice cooked is relatively large), and the comparison circuit 59 outputs a high level signal to line 1. ．． Give to 6. When the count value of the counter 73 is equal to or greater than the value equivalent to 7 minutes but smaller than the value equivalent to n 9 minutes (in other words, when the amount of rice cooked is medium), a high level signal is output from the comparator circuit 58 and this is detected. It is applied to one input terminal of the AND circuit 110, and a low level signal is output from the comparison circuit 59, which is inverted to the input terminal 122 and the high level signal to the other input terminal of the circuit 110. (J given λ, exactly, ψ is A N +-) Circuit 11
A high level signal is output from (') and applied to lines 1-5. When the amount of cooked rice detected by the IC is relatively small, the transfer terminals 1 to 92.98 whose terminals are connected to the line 14 are in a conductive state, When the detected amount of cooked rice is medium, the terminals 1 to 1 to 1 to 93 whose terminals are connected to line 15
．． 99 indicates a conductive state, and if the amount of cooked rice detected is relatively large, transfer gates 1 to 9/I, 100 whose terminals are connected to lines 1-6, indicate a conductive state. It becomes like this. At this time, the 10th. 11th゜12th temperature value storage section 35,
36. The temperature information stored in 37 is also for correcting the heater power-off temperature 1)l (the temperature value stored in the thirteenth temperature value storage unit 38, that is, 112°0). , each of these stored temperature values is selectively applied to the input terminal TY of the adder circuit 69 according to the length of the time period, and in the six adder circuits, the input terminal T-Y of the adder circuit 69 Value addition circuit 6
Numerical signal from 8 (i.e., temperature ratio for evening power outage l') l
In contrast, for rice cooking, the detection circuit 127 further adds the adjustment value according to the detected amount of cooked rice (IJ tightened), and the rice cooking amount detection section 127 adds the amount It works to compensate for the detected amount of cooked rice. Also,
Similarly, selectively conductive l-transphages [-98
, 99, 100. 9th. The time value stored in the 10th time value storage unit 47, 48.49 is also the same as the 7-degree cooking heating reference time N (the time value stored in the 11th time value storage unit 50, that is, 30 seconds). These stored time values are selectively given to the input terminal Y of the adder circuit 71 according to the length of the time -rb, and the values C in the adder circuit 71 are The input time value is added to the numerical signal from the addition circuit 70 (that is, the time value corresponding to the amount of cooked rice detected by the rice amount detection circuit 127 with respect to the 7-degree cooking heating reference time N). )
It further acts to supplement the detected rice cooking amount by adding the additional time value of the rice cooking amount detection section 127 to -ULt. Now, at the subsequent time 1G, the preparation of the steel 5 is determined by the cooked rice quantity detection unit 127 with respect to the fully cooked rice temperature corresponding to the output from the addition circuit 69 (i.e., the heater power cutoff temperature Dz (112°C)). When the temperature reaches the temperature value obtained by adding the temperature value corresponding to the amount of rice cooked and the temperature value corrected by the correction means 129), each input value to the input terminals Δ and B of the comparator circuit 61 becomes in the relationship A≧B. Since a high level signal is output from the comparison circuit 61, the R-S flip-flop 105 is set. Then, the low level signal from the gate output terminal d of the R-87 lip 1] tube 105 is given to the AND circuit 112, and the output of the AND circuit 112 is inverted to the [-1- level signal, so the heater output The drive of the control circuit 84 is stopped, and in response, the heater drive circuit 83 stops outputting the goo 1 to signals S(+ to keep the liac 14 in the turned-off state, that is, to cut off the power to the heater 6. Then, the rice cooking process is completed.At this time, the high level signal from the set output terminal Q of the R-S flip-flop 105 is output to the AND circuit 1.
14 and 115, the AND circuit 114 allows the pulse signal P+ to pass, and in response, the seven-degree cooking control means 130 functions to shift to the uneven stroke. [In short, the temperature of steel 5 is
The temperature value (seventh
, No. 8. Any one of the temperature values stored in the ninth) temperature value storage unit 32, 33, 34) and the corrected temperature value by the correction means 129 (the 10th, 11th, 12th temperature value storage unit 35, 36) When the rice cooking process reaches the cooking temperature, which is the sum of any one of the temperature values stored in . Describe the action in the process. In the case of this embodiment, the above-mentioned cooking temperature is 114°O according to the stored contents of the seventh to thirteenth temperature value storage units 32 to 3B.
and 122°O. The counter 75 in the 7-degree cooking control means 130 starts the pulse signal 1]1 from the time the power is turned on.
Therefore, at time 16, the count value is at least larger than the number candy signal output from the tightening circuit 71 (a value corresponding to 100 seconds at the maximum in this embodiment), and as a result, the count value of the comparator circuit 64 Each input value to the input terminals A and 1B has a relationship of A<8, and the comparison circuit 64 outputs a [1-level signal.
The other counters 74 within 1) start counting from time 16, so at this point each numerical value input to the input terminals A and B of the comparator circuit 62 is A≧B.
A high level signal is output from the comparator circuit 62 due to the relationship. Then, when the heater 6 is cut off at time [-6], the temperature of the steel 5 gradually decreases after reaching -1- as shown in FIG.
Then, at time 1T, the temperature of the steel 5 reaches the 7 degree cooking start temperature r)r(10
3°0), the input terminal A of the comparator circuit 63,
[Each input value of 3 to 4 has a relationship of A a R and a high level signal is output.The trigger circuit 78 receives the high level signal and outputs a trigger pulse P3.] Then, the input terminal 75 is initialized. Then, the input values of the input terminals A and B of the comparison circuit 64 meet the relationship △≧3 (7 A high level signal is output from the comparison circuit 64, and in response, high level signals are applied to all input terminals of the AN[1 circuit 115, and the output of the AND circuit 115 becomes the high level signal Q. As a result,
” - Receives a high level signal from the AND circuit 115C)
The heater drive circuit ε33 turns on the I~Liac 14 to re-energize the heater (5), and in response to this, 2 [q cooking heating is performed.At this time, the count value of the counter 75 is as follows. The elapsed time from time t7 when the temperature of the steel plate decreased to 103°C is shown as J, and at time t8, the value of the counter 1 changes to the time corresponding to the output from the tightening circuit 71 (all, 7 Standard heating time N (
30 seconds), the comparison circuit 6
Since the input values to the input terminals A and B of A4 are in the relationship A<B, the output of the comparator circuit 64 is inverted to the l'l- level signal, so the output of the A N1 circuit 115 is also In reverse, the heater drive circuit 83 turns off the triac 14, and the heater 6 is cut off and C2f is turned off.
σ Cooking heating is stopped. After this, the temperature of steel 5 rises at once by heating 7 degrees, and then rises to 10 degrees.
At each time t9 when the temperature drops to 3°C. At tt+, the heater 6 is energized again and heating is performed for 7 degrees in the same way as in the book. It is stopped at each time Tro, [12] when the time corresponding to the start of the time is over. Then, at time t13, when the erratic driving time M (15 minutes) stored in the 12th time value storage unit 51 has elapsed after time 16, the count value of the counter 74 corresponds to the erratic driving time M. Since the output of the 41C comparator circuit 62 is inverted to a low level signal so as to exceed the value
[) The state in which the circuit 115 outputs the low level signal and the state in which the heater drive circuit 83 is stopped are maintained, and the uneven stroke is completed. Therefore, when the output of the comparison circuit 62 is inverted to the [1- level signal as described above, the inverter 12! ') is inverted to a high-level signal and the trigger pulse P3 is output from the trigger circuit 79. This trigger causes the R-S flip-flop 103 to be re-hit by the pulse P3. The process moves to a heat retention process using a heat retention heater (not shown). In short, in the uneven process, the temperature of the steel 5 is 7
The heater 6 is energized again as soon as the temperature for starting cooking [)r has fallen to 103°C, and the energization time is detected by the rice cooking amount detection means 127 for 30 seconds, which is 1/2 hour N for 7 degrees cooking. The time value according to the amount of cooked rice (5th.
6th. any one of the time values stored in the seventh time value storage section 44, 45, 46) and the correction value (8th, 10th, 11th) by the correction means 129; Memory part 47°48. /19)
711 M It reached between 11.1 and 2,
In this example, the control of turning off the heater 0 and ending the second heating 11 is repeated.
The heating time is 5th to 11th time 11n.
Memory part 44 no imo! -50 for a period of 30 to 70 seconds (changed depending on the memory contents.) Up to this point, the odor -C is the boiling detection signal Sl is output at the time [4 (J) and the heater 6 is activated. After the output is reduced to half of the rated value, the humidity of steel 5 (1 Figures 5 and 6, which are similar to Figures 3 and 4 of the previous model, show the effect when the temperature of the steel 1) decreases after the output of the heater 6 is reduced in this way. Let me explain with reference to the following.In other words, when the output of the heater 6 is reduced to 21', the temperature of the steel plate decreases.
This phenomenon is caused by the water inside the steel 5! This is a phenomenon that occurs when the boiling detection signal S7 is erroneously output (in other words, when the boiling detection signal S7 is incorrectly output). The seasonings such as soy sauce put into the steel pot 5 burnt at the bottom of the pot 5.
This is thought to be due to the fact that the gap between the temperature of the water in the steel 5 and the temperature detected by the thermistor 9 increases. Therefore, when the output of the heater 6 is halved at time 14 in FIGS. 5 and 6, the temperature of the steel 5 at that time (i.e., the boiling detection means 128 is in the boiling state), as described above. The temperature detection signal 3 (1) corresponding to the temperature of the steel 5 at k is stored in the memory circuit ε32 in the boiling detection compensation means 131. The circuit 67 subtracts the sixth temperature (the numerical value stored in the storage section 31 (equivalent to 3°C)) from the stored value in the storage circuit 82, and calculates the temperature value 1p corresponding to the subtraction result. is applied to the input terminal of the comparator circuit 60. Therefore, after that, when the temperature of the steel 5 drops to the above-mentioned temperature value Tp (time [41), the output of the comparator circuit 60 is inverted to a high level signal. In response to this, when the R-S flip-flop] is turned on, the trigger circuit 76 is driven and the trigger pulse P3 from the trigger circuit 76 is activated. The sheet L-register 81 is initialized. Therefore, the output of the AND circuit 112 is inverted to a J-level signal, and the output of the AND circuit 113 is inverted to a high-level signal, which is connected to the C1 heater drive circuit 83. In response to this, the heater 6 begins to generate heat at its rated output, that is, an output of 600 watts 1.Also, as described above, the shift 1 to register 81 are initialized. In response to this, the boiling detection means 127 performs the same boiling state detection operation as described above.For example, when the comparison circuit 65 outputs the boiling detection signal Sz at time t42, the boiling detection means 127 performs the same boiling state detection operation as described above. The output is halved.Furthermore, if the temperature of the unit 15 decreases again after this, the same operation as described above is repeated, and the boiling detection compensating means 131 adjusts the boiling detecting means 12 as follows.
It functions to make the detection operation of No. 8 more accurate. According to the present embodiment described above, the following effects can be achieved. That is, instead of detecting the boiling state of the water in the pot 5 based on an absolute predetermined temperature limit as in the conventional method, the boiling state of the water in the pot 5 is detected when the water in the steel 5 reaches a boiling state. The temperature gradient of the steel 5 has become below a certain gradient (specifically, the amount of change in the temperature of the steel 5 within a predetermined reference time has been stored in the fifth temperature value storage unit 30 Since the configuration is configured to detect based on the temperature value (below a certain comparative temperature value (2°C)), the contact state between the heat-sensitive cap 7 and the bottom of the pot 5, and the thermistor 9 constituting the temperature detection means 25. Or variations in the circuit constants of the A-D converter 24 and changes in its characteristics over the years, changes in atmospheric pressure, or fluctuations in the boiling point caused by seasonings being put into the pot 5 when making cooked rice. Even if there is such a problem, the boiling state of the water in the pot 5 can be accurately detected and overridden. In addition, when detecting the boiling state in this way, due to the temperature increase gradient of the steel 5 changing depending on the amount of rice cooked,
When the amount of cooked rice is different, there is a possibility that the boiling detection as described above may be inaccurate, but in this embodiment = 42-, the boiling detection is performed according to the size of the detected amount of cooked rice. Since we have adopted a structure that changes the humidity gradient of the steel plate that sometimes serves as a measuring cup (specifically, a structure that changes the reference time required when measuring the temperature gradient), the boiling state of the water in the steel plate 5 can be detected by Even if the amount of rice to be cooked differs, it can always be done accurately. In this embodiment, the rice cooking control is performed by causing the heater 6 to generate heat at the rated output until a boiling state is detected, and then reducing the output of the heater 6 by half. J
: Since the detection of the sea urchin boiling state is accurate, -1- it is possible to strictly control the rice distribution, and it is possible to cook the rice deliciously and to achieve the so-called "middle papa", which is one of the 1- bordame dishes ++. As long as the conditions can be fully met, the rice can be cooked with less stickiness, and overall the rice is cooked -1.
- It is possible to achieve good bending. Of course, since the boiling state in the steel 5 is accurately detected in this way and the output of the heater 6 is halved after the boiling is detected, when this structure is applied to porridge cooking control, , which can reliably prevent boiling over. Furthermore, in this example (yo,
When a comparatively large amount of unnecessary moisture remains in the steel 5 in the culm with a large amount of cooked rice detected by the rice cooking amount detection means 127, in other words, in the doshi-up 111, the power cutoff temperature of the culm and the jetter 6, that is, the rice. By raising the cooking temperature, this side of the mustard rice can be cooked well. Moreover, in this case, the correction means 129 is installed, and the rice cooking amount detection means 1
Since the rice cooking amount detected in step 27 is corrected according to the length of the period during which the water in the steel 5 is in a boiling state, the rice cooking can be controlled according to the amount of rice cooking and the ratio of rice to water during cooking. can be carried out more precisely. Also, during the uneven journey (
The cooking heating time is also changed to a time corresponding to the amount of cooked rice detected by the rice cooking amount detection means 127 and corrected by the correction means 129, so that it is possible to prevent rice from becoming alpha. You can do it as much as you need, and you can make well-cooked rice even more delicious. In addition, when making cooked rice, errors in boiling detection caused by scorching of seasonings such as soy sauce put into the steel 5 are compensated for by the boiling detection compensating means 131. "2-stated": The inside of the steel 5 is in a special state, etc., and the temperature i detected by the temperature detection means 25 and the actual steel 5 are different.
Even if there is a difference between the temperature within the boiling pot and the temperature within the boiling pot, the boiling state of the water within the sieve 5 can be detected extremely accurately. Furthermore, in the "-registered embodiment," the function of the boiling detection means 128 is activated only when the temperature of the steel 5 reaches the lower limit temperature (90° C.) stored in the third temperature value storage section 28. Therefore, there is no possibility that a period during which the temperature gradient is flat, such as at the time when the temperature of vA5 shown by G in Fig. 3 is in a flat state, will be mistakenly detected as a boiling state. . A second embodiment of the invention is shown in FIG.
Hereinafter, only the differences from the first embodiment will be explained. That is, the second embodiment is characterized in that, in place of the boiling detection means 128 in the first embodiment, a boiling detection means 132 having a different function is provided. 132 will be described. In the boiling detection means 132, 133 is a shift 1 register having, for example, 12 unit registers, and the memory arc of the 12th unit register 133a is given to the input terminal of the subtraction circuit 1371. ing. Register 133 to shift 1 above. A comparison circuit 135 that receives the outputs of the subtraction circuit 134 and the subtraction circuit 13/I at the input terminal B is similar to the shift 1 register 81, the subtraction circuit 66, and the comparison circuit 65 in the first embodiment. It is equipped with the functions of 136.137.13ε
3 is the 15th. 16th. The seventeenth humidity value storage section stores the reference humidity of 2° C. and 1° C., respectively, in the embodiment of the present invention.
．． Numerical values corresponding to 5°C and 1°C are stored. Further, 139, 140, 141 are each of the storage units 136, 13
7.L-lansf 1 installed corresponding to 138 respectively
The terminals of each goo 1 to game 1 are connected to lines L+ and l-2.
, 1, -3. In this embodiment, the temperature detection signal Sd on the right side of the ring is input to the input terminal [] of the subtraction circuit 13/I, and the unit registers 133-/I6 of shift 1 to register 133 are input to -C in this embodiment.
- Memory data of a, i.e. 120 seconds (2 minutes) ago (1) I
I; 5-point temperature detection (i'' No. 8 Sd is input to the input terminal of the subtraction circuit 134. Therefore, there is a number C that is applied to the input terminal B of the comparison circuit 135 from the subtraction circuit 134. "r Ha, constant tli? Itil
Tal 2 minutes Ni di Lj Le 615 (D) Akira IU
J-If II (, 1 corresponds to 1. At this time, 1 is determined by the amount of cooked rice detected by the rice cooking amount detection means 127, and any one of 1 to 139 to 141 is set to One exhibits a conductive state and J3, the 15th
．． Sixteenth and seventeenth temperature value storage units 136, 137, 13
Any one of the memory numbers of ε3 is applied to the input terminal 7Δ of the comparison circuit 135 (ψtemperature and -C).Therefore, the input terminals A and B of the C1 comparison circuit 135 When each human power value has a relationship of △≧F3, 19!When the temperature 1-yr value of the steel 5 that rises in A3 becomes below the above reference temperature in 2 minutes, a boiling signal is generated which is a high level signal. In short, in this embodiment, C also detects the temperature when the temperature gradient of the steel 5 becomes equal to or less than a predetermined target temperature gradient (specifically, when the fifth temperature rises within a certain period of time) When the amount of change in rice becomes below a predetermined reference temperature), a boiling detection signal Sz is output, and the reference temperature is automatically changed depending on the amount of rice cooked. It is possible to achieve the same effect as in the example. In each of the above examples, the temperature of the steel 5 is 70°C to 80°C.
The rice cooking amount detection means 127 is configured to detect the amount of rice cooked based on the time required for the rice to rise. Storage part 2
6. The stored value in 27 is not limited to this, and the amount of rice cooked can be detected by measuring the entire weight of the fifth item. It is also possible to set [no]. Of course, each of the other temperature value storage units 28 to 39, 136 to 138 and the temperature value storage unit 4
The storage contents of 0 to 51 are not limited to the above-mentioned embodiments, and the 14th storage section 3 is especially used for 7 degree cooking heating control.
The numerical value stored in 9 may be replaced by the numerical value stored in the storage circuit 82. Furthermore, in each of the embodiments described in Section 2, the measurement of the duration of the boiling state by the correction means 129 is performed using the numerical value stored in the fourth temperature value storage section 29 (
110 degrees Celsius), but instead, the point in time when the temperature of the steel 5 suddenly rises is detected, and the duration of (boil!) is measured based on the detection result. -C is also good.Also, in each of the above embodiments, the rice cooking amount detected by the rice cooking amount detecting means 12'l is ranked into three levels, but this is further ranked into multiple levels (').
In this case, of course, the configurations of the boiling detection means 128 or 132 and the correction means 129 will be changed accordingly, but by having such a configuration, boiling detection can be performed. This can be done more precisely. In each of the above-mentioned embodiments, the electric power generated during 7-degree cooking is avoided by time control. However, other configurations may be used as long as the average power of the heater 6 is changed. The energization time of the J3 heater 6 does not need to be constant each time as in each of the above embodiments, and may be made to become shorter sequentially during each 7 degree heating, for example. In addition, instead of the heater output control circuit 84, a circuit configured to reduce the output of the heater 6 using a phase control method may be used, and in place of the reactors 1 to 14, a relay or the like may be used. Other switching elements may also be used. Furthermore, - in the above embodiment, only the normal rice cooking operation was explained, but in addition to this, other rice cooking functions such as porridge cooking and brown rice cooking are also available.
Of course, it is also possible to add. In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be practiced with moderate modifications without departing from the gist thereof. ``Effects of the Invention'' As is clear from the explanation in Section 2 of the present invention, it is possible to detect the boiling state of water in a pot at all times (accurately) regardless of the amount of rice being cooked. In addition, based on the detection results in (a), the heater output can be reduced at exactly one time after the water in Cw4 has boiled, and it is possible to control the control to cook rice deliciously or to cook porridge. Control to prevent boiling of strawberry from boiling over should be done accurately, and it is also possible to automatically compensate when a boiling state is erroneously detected due to external factors.
It is a Shino that has excellent effects such as monkeys.

[Brief explanation of the drawing]

Figures 1 to 6 show the first embodiment of the rice cooker; Figure 7 is a block diagram of the electrical configuration; , Fig. 3 is a change characteristic diagram of pan temperature and heater output, Fig. 4 is a timing diagram based on the output waveform of each part in Fig. 1, and Fig. 5 is a graph of pan temperature and heater output in a different state from that shown in Fig. 3 above. The change characteristic f/ of the same evening output is shown in the figure.
FIG. 6 shows the output waveforms of each part in FIG. 1 in state C, which is different from FIG. A diagram equivalent to Figure 1 shown below.
There is C. In the figure, 1 is the rice cooker body, 5 is the steel, 6 is the heater, 7 is the heat sensitive key 17, 9 is the reamister, 10 is the pot soup/tsuji, 1
ζ3 is a control circuit, 25 is a temperature detection means, 83 is a heater drive circuit, 84 is a heater output control circuit, 101 is a start switch, 102 is a stop switch, 126 is a timing means, 127 is a cooking amount detection means, 128, 132 are Boiling detection means, 129 correction means, 130 7 degree cooking control means,
Reference numeral 131 indicates a boiling detection means. Applicant: Toshiba Corporation

Claims (1)

[Scope of Claims] 1. Temperature detection means for outputting a temperature detection signal according to the temperature of the pot, time measurement means for outputting a time signal indicating the elapsed time during rice cooking operation, and a rice cooking amount signal according to the amount of rice cooked. a rice cooking amount detection means that outputs a rice cooking amount, and measures a time-series gradient of the pot temperature based on the temperature detection signal and the time signal, and controls the pot temperature when the measured temperature gradient becomes equal to or less than a predetermined target temperature gradient. boiling detection means that determines that the water in the container is in a boiling state and outputs a boiling detection signal; a heater output control circuit that reduces the output of a heater for cooking rice when the boiling detection signal is output; and the boiling detection means. The temperature detection signal at the time when the signal is output is stored, and a certain compensation temperature value is subtracted from the stored value, and after this, when the temperature detection signal decreases to the above subtraction result, the temperature detection signal of the heater is boiling detection compensating means for increasing output, and the boiling detecting means is configured to change the target temperature gradient so that the larger the amount of rice indicated by the rice cooking amount signal is, the smaller the target temperature gradient becomes. A rice cooker. 2. The boiling detection means is provided to measure the temperature gradient based on the amount of change in the temperature detection signal within a predetermined reference time, and the boiling detection means is provided to measure the temperature gradient based on the amount of change in the temperature detection signal within a predetermined reference time. The rice cooker according to claim 1, characterized in that the rice cooker is configured to change as follows. 3. The boiling detection means is provided to measure the temperature gradient by comparing the amount of change in the temperature indicated by the temperature detection signal within a certain period of time with a reference temperature, and the boiling detection means is configured to measure the temperature gradient by comparing the amount of change in the temperature indicated by the temperature detection signal within a certain period of time with a reference temperature, and the boiling detection means The rice cooker according to claim 1, wherein the rice cooker is configured to change the amount so that the amount becomes lower as the amount increases. 4. The boiling detection means is configured to enable the boiling detection function only when the temperature indicated by the temperature detection signal exceeds a predetermined lower limit temperature. The rice cooker described in. 5. Claim 1, characterized in that the rice cooking amount detection means is configured to detect the rice cooking amount according to the magnitude of the amount of change in temperature per unit time indicated by the temperature detection signal. The rice cooker described in.